Create Add_Two_Numbers.js

Author: ignacio-chiazzo

LeetcodeProblems/Add_Two_Numbers.js

@@ -0,0 +1,64 @@
+/*
+Add Two Numbers
+https://leetcode.com/problems/add-two-numbers/
+
+You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.
+
+You may assume the two numbers do not contain any leading zero, except the number 0 itself.
+
+Example:
+
+Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
+Output: 7 -> 0 -> 8
+Explanation: 342 + 465 = 807.
+*/
+
+/**
+ * Definition for singly-linked list.
+ * function ListNode(val) {
+ *     this.val = val;
+ *     this.next = null;
+ * }
+ */
+/**
+ * @param {ListNode} l1
+ * @param {ListNode} l2
+ * @return {ListNode}
+ */
+    
+var addTwoNumbers = function(l1, l2) {
+  if(l1 === null) {
+    return (l2 === null) ? new ListNode(0) : l2;
+  } else if(l2 === null)
+    return l1;  
+  
+  var elem = l1.val + l2.val;
+  var number = new ListNode(elem % 10);
+  var carry = (elem >= 10) ? 1 : 0;
+  l1 = l1.next;
+  l2 = l2.next;
+  
+  const head = number;
+  while(l1 !== null || l2 !== null) {
+    var l1elem = 0;
+    var l2elem = 0;
+    if(l1 !== null) {
+      l1elem = l1.val;
+      l1 = l1.next;
+    }
+    if(l2 !== null) {
+      l2elem = l2.val;
+      l2 = l2.next;
+    }
+    
+    elem = l1elem + l2elem + carry;
+    number.next = new ListNode((elem % 10));
+    number = number.next;
+    carry = (elem >= 10) ? 1 : 0;
+  }
+  if(carry === 1) {
+    number.next = new ListNode(1);
+    number = number.next;
+  }
+  return head;
+};